LA Galaxy coach Bruce Arena was furious with the dismissal of Robbie Keane in their 5-2 Champions League win over Isidro Metapan.
Former Tottenham and Liverpool striker Keane saw red in the 70th minute.
Arena barked: "Making a transition into this circus sometimes is unbelievable. It's very difficult on MLS teams. I sometimes wonder why we spend all the resources and time we do in this competition when sometimes it looks really bizarre.
"I don't know. The ref missed the call and typical, we've seen in these competitions, the referees think they're bigger than the game itself and they've got to put themselves ahead of everything, I guess he felt he should not be, I don't know.
"Robbie spoke, said something, whatever, but when a referee misses a call like that, he's got to be big enough to kind of ignore it and let the game go on. So a player gets a yellow card for diving when he's fouled and then obviously a red card for, I don't even know. They didn't explain anything to us."